Device for supplying a drive element

ABSTRACT

The invention relates to a device for supplying a hydraulic medium to a rotatably mounted drive element in a transmission case, the hydraulic medium being routed to a channel in the drive element by way of at least one channel in a coaxially adjacent element which corresponds to the drive element. Structurally favorable and reliable supply with hydraulic medium is achieved in that the drive element is nonrotatably connected to the other element and that the contact connection is at least one unthreaded conduit which is inserted tightly into the two channels and which extends directly from the element to the drive element.

The invention relates to a device for supplying a hydraulic medium to adrive element rotatably mounted in a transmission case, as claimed inthe preamble of claim 1.

In general, drive elements rotatably mounted in a transmission case—onlyone example being the pulley set of continuously variable transmissionin a motor vehicle, with a hydraulically adjustable loose pulley whichcan be axially moved relative to the fixed pulley—are transmitted by wayof channels in the shaft which bears the drive element by a coaxiallyconfigured element which is connected to the hydraulic control. Inparticular, when several separate channels are necessary for hydrauliccontrol, this results in a significant production engineering effort anda considerable weakening of the indicated shaft due to the requiredshaft bores.

The object of the invention is to propose a device of the generic typewhich enables reliable hydraulic supply of a drive element without shaftholes.

This object is achieved as claimed in the invention with thecharacteristics specified in claim 1. Advantageous developments of theinvention are cited in the other patent claims.

As claimed in the invention, it is proposed that the drive element isnonrotatably connected to the other element and that the contactconnection is at least one unthreaded conduit which is inserted tightlyinto the two channels and which extends directly from the element to thedrive element. At least one unthreaded conduit turns with the elementwhich supplies the hydraulic medium; shaft bores can accordingly beomitted. Furthermore, at least one unthreaded conduit forms a connectionwhich to a limited degree allows universal movements and axialcompensation between the drive element and the other element; thisresults in supply of the hydraulic medium to the drive element which isreliable even with unfavorable tolerance pairings and operatingconditions (temperature, load) or axial slip. Another major advantage isthat if necessary the supplying element can be a component of thetransmission which also performs other functions (for example, routingthe hydraulic medium through a coaxially adjacent gear which turns withthe drive element).

At least one unthreaded conduit can extend radially within a rollerbearing which is provided between the drive element and the adjacentlylocated element. This makes possible supply of the drive element by wayof at least one unthreaded conduit even if support is indicated betweenthe drive element and the other element for transmission engineeringpurposes.

Preferably the inner ring of the roller bearing can sit on the neck ofthe drive element and at least one unthreaded conduit can run in acorresponding recess of the neck. The unthreaded conduit can thus bepartially integrated into the drive element without added constructioneffort and space consumption.

Simple axial locking is achieved by the unthreaded conduit beingprovided with a radial projection by means of which it is held on thefront between the inner ring of the roller bearing and the followingdrive element.

Furthermore, for easy installation of the transmission element theunthreaded conduit on the two ends can bear gaskets for sealing with theadjoining channels in the drive element and the other element. Thismakes it possible to easily assemble the transmission elements andenables routing of the hydraulic medium which is insensitive tovibrations and which is guided hermetically sealed even in the event oflimited universal and axial relative movements.

Especially preferably provision can be made for several unthreadedconduits which are distributed over the periphery of the drive elementand which correspond to the appropriate channels in the drive elementand in the other element. Either at the same time larger hydraulicamounts or with separate channels different hydraulic functions can becontrolled by way of the unthreaded conduits.

Furthermore, the annular hydraulic chamber can be supplied using anactuating piston for movement of the drive element by way of thechannels and unthreaded conduits. By using unthreaded conduits, inaddition to the aforementioned advantages, channel routing within thedrive element can also be simplified, because the unthreaded conduits ifnecessary enable direct supply of the hydraulic medium to the annularhydraulic chamber.

Advantageously there can be spline-teeth as the nonrotatable connectionbetween the drive element and the other element; they are configured asan unthreaded connection radially within the roller bearing on the neckof the drive element and on the annular projection of the other element.This makes possible a structurally favorable and compact transmissiondesign which moreover yields further simplification of assembly andaxial tolerance compensation.

Finally, in one preferred application of the invention the drive elementcan be a driven pulley set of a continuously variable transmission formotor vehicles and the other element can be the differential gear caseof a torsen differential, the output to the axle of the motor vehicleextending through the hollow shaft of the pulley set and thetransmission ratio of the pulley set to the looping means beingcontrollable by way of channels and the unthreaded conduits. The conceptof a torsen differential is known in mechanical engineering andespecially in transmission engineering.

One embodiment of the invention will be described in detail below.

The attached schematic shows in a longitudinal section a device forhydraulic supply of the driven pulley set of a continuously variabletransmission for a motor vehicle.

In the drawing, 10 generally designates a drive assembly which isrotatably mounted in an only partially shown transmission case 12 andwhich is composed essentially of an only partially shown driven pulleyset 14 as the drive element and a torsen differential 16 which islocated coaxially adjacent to it as the other element.

The pulley set 14 is one part of the continuously variable transmissionfor motor vehicles and interacts in the conventional manner by way of achain or an articulated belt with a drive pulley set (not shown) locatedon the input shaft of the transmission.

The driven pulley set 14 has a fixed pulley (not shown in the drawings)which forms a common component with an adjoining hollow shaft 18. Thefixed pulley is supported to be axially immovable in one wall of thetransmission case 12 by way of a double-row taper roller bearing.

On the hollow shaft 18 the loose pulley 20 is guided to be axiallymovable, a spline connection which is designated as 22 producingpositive locking in the peripheral direction. Here the loose pulley 20as shown in the drawings to the left is pretensioned by means of ahelical compression spring 24 which is supported on the guide section26. The guide section 26 is connected permanently to the hollow shaft 18by an annular laser weld at 28.

To move the loose pulley 20 relative to the fixed pulley which is notshown, between the guide section 26 and the loose pulley 20 by means ofannular sheets 34, 35 which have been welded together and which arefixed on the loose pulley 20, two annular hydraulic chambers 30, 32 areformed which are sealed by gaskets which are generally designated as 36and are divided by an annular actuating piston 38. The actuating piston38 which is permanently connected to the guide section 26 by way of anedged connection 40 acts as the reaction element to the correspondingaxial adjustment of the loose pulley 20 when the hydraulic chambers 30,32 are pressurized accordingly.

The guide section 26 has an annular neck 42 with the inner ring 44 ofthe roller bearing or ball bearing 46 sitting on its outer periphery.The ball bearing 46 is held in the transmission case wall 48 in acorresponding recess 50 and thus acts as another pivot bearing for thepulley set 14.

On the inside periphery of the annular neck 42, for example in the planeof rotation of the ball bearing 46, spline-teeth designated as 52 ingeneral are machined and interact with the corresponding spline-teeth onthe sleeve-shaped projection 54 of the differential gear case 56 of thetorsen differential 16 as a driving connection.

In the differential gear case 56, three worm gear pairs 58 which aredistributed uniformly in the conventional manner over its periphery aresupported and engage the corresponding driven gears 60, 62. The drivengears 60, 62 sit nonrotatably on driven shafts 64, 66, of which thedriven shaft 64, through the hollow shaft 18 by way of a drive pinionwhich is not shown and a front differential, drives the front wheels ofthe motor vehicle, and the driven shaft 66, by way of a connecteduniversal shaft and the rear differential, drives the rear wheels of themotor vehicle.

The drive shaft 64, in addition to the support which is not shown, issupported in the area of the drive pinion in one loading direction byway of an axial bearing 68 on the hollow shaft 18, its one retainer ring70 being held on a locking ring 74 which is forced into an annulargroove 72.

The torsen differential 16 and its operating parts are lubricated withlubricating oil from the front differential which is not shown, a feedchannel 76 which is provided in the driven shaft 64 discharging into thedifferential gear case 56. The return of the lubricating oil takes placein the opposite direction through the hollow shaft 18, in addition tothe axial bearing 68 two radially supporting needle bearings 78 (onlyone needle bearing 78 is shown, the second is positioned approximatelyin the area of the fixed pulley) between the hollow shaft 18 and thedriven shaft 64 being lubricated.

The torsen differential 16 is made fully encapsulated in order to ensureonly lubrication of the described operating parts with the differentiallubricating oil (a hypoid oil). For this purpose, there is an annularcover part 80 which encloses the differential gear case 56 and whichseals the differential gear case 56 to the outside in conjunction withgaskets 82. Another gasket 84 is inserted in the area of thespline-teeth 52 between the hollow shaft 18 and the sleeve-shapedprojection 54 of the differential gear case 56.

The front seal of the differential gear case 56 finally effects atubular piston ring insert 86 with a connecting flange 88 with anothergasket 56 which it is screwed (screws 92) tightly to the differentialgear case 56 and the axial seal (not shown).

The piston ring 86 and accordingly the differential gear case 56 arepivotally mounted directly following the connecting flange 88 by meansof another roller bearing or ball bearing 94 in a corresponding receiver96 on the housing, the annular section 97 of the piston ring insert 86which is provided with piston rings 98 in the corresponding outsidegrooves 99 projecting, as is apparent, into a cylindrical hole 100 ofthe housing part 102 which has the receiver 96.

The rotationally symmetrical sealing sleeve 104 which is inserted intothe piston ring insert 86 projects axially over the annular section 97and is sealed to the housing part 102 by way of a rotary shaft seal 124so that hydraulic medium cannot emerge from the channels 106, 108.

The hydraulic chambers 30, 32, 32 a can be supplied on alternating sideswith a pressurized hydraulic medium for control of the drivingtransmission of the continuously variable transmission by way of thepiston ring insert 86 and the rotationally symmetrical sealing sleeve104 which is inserted into it, by way of the illustrated channels 106which are each provided with a uniform reference number in the housingpart 102, by way of the channels 108 which are formed by thelongitudinal grooves in the piston ring insert 86, by way of thechannels 110 which are machined in the differential gear case 56, andfinally by way of the corresponding channels 112 in the guide section 26(only one channel 112 is shown in the sectional view of the drawing).

The hydraulic connection between the channels 110 in the differentialgear case 56 and the channels 112 in the guide section 26 is formed bythree unthreaded conduits 114. The unthreaded conduits 114 each projectwith the interposition of gaskets 116 on the one hand into acorresponding front recess of the guide section 26 and of thedifferential gear case 56, said unthreaded conduits being guided throughrecesses 118 of the guide section 26, which are open radially to theoutside and which are semicircular when viewed in cross section, withinthe inner ring 44 of the ball bearing 46.

The unthreaded conduits 114 (to move the loose pulley, as stated, thereare three unthreaded conduits 114 which are distributed uniformly overthe periphery of the guide section 26 and of the differential gear case56) are held by means of radial projections 120 which are molded ontothem between the inner ring 44 and the front recess 122 of the guidesection 26. Axial guidance of the unthreaded conduit can also beselectively guaranteed by contact of the end surfaces.

1. Device for supplying a hydraulic medium to a rotatably mounted driveelement in a transmission case comprising a hydraulic medium routed to achannel in the drive element by way of at least one channel in acoaxially adjacent element which corresponds to the drive element, thedrive element is nonrotatably connected to a second element the contactconnection between the drive element and the second element comprises atleast one unthreaded conduit, inserted tightly into two channels andextends directly from the second element to the drive element.
 2. Thedevice as claimed in claim 1, wherein at least one unthreaded conduitextends radially within a roller bearing which is provided between thedrive element and the adjacently located second element.
 3. The deviceas claimed in claim 1, wherein an inner ring of the roller bearing sitson neck (42) of the drive element and wherein at least one unthreadedconduit extends in a recess of the neck.
 4. The device as claimed inclaim 3, wherein the at least one unthreaded conduit is provided with aradial projection, and is axially held on the front between the innerring of the roller bearing and the following drive element or is heldwithout the radial projection by axial contact with the front surfaces.5. The device as claimed in claim 1, wherein the at least one unthreadedconduit on two ends bears gaskets for sealing with adjoining channels inthe drive element and the second element.
 6. The device as claimed inclaim 5, comprising a plurality of unthreaded conduits distributed overthe periphery of the drive element and which correspond to theappropriate channels in the drive element and in the second element. 7.The device as claimed in claim 6, wherein an annular hydraulic chamberis supplied using an actuating piston for movement of the drive elementby way of the channels and unthreaded conduits.
 8. The device as claimedin claim 1, wherein the nonrotatable connection between the driveelement and the second element comprises spline-teeth, wherein thespline teeth are made radially within the roller bearing on a neck ofthe drive element and on an annular projection of the second element asan unthreaded connection.
 9. The device as claimed in claim 1, whereinthe drive element is a driven pulley set of a continuously variabletransmission for motor vehicles and the second element is thedifferential gear case of a torsen differential, an output to the axleof a motor vehicle extends through a hollow shaft of the pulley set andthe transmission ratio of the pulley set to looping means beingcontrollable by way of channels and the at least one unthreaded conduit.10. The device as claimed in claim 1, wherein the drive element is apulley set.
 11. The device as claimed in claim 1, wherein the secondelement is a differential gear case.